Immediately responsive fluid flow operated switch with normally closed spring contact in flow channel

ABSTRACT

A fluid flow transducer for disposition in one or more fuel feedlines of a fuel-injected engine for analyzing and timing the engine. The transducer includes a normally closed resilient movable contact in the transducer which is directly impinged by the flowing fuel to open an electrical circuit to generate signals which are indicative of the rotational speed of the engine and the frequency and time duration of fuel flow through each fuel line.

United States Patent [72] inventor Raymond Pisors Morton Grove, 111.

Feb. 20, 1970 Dec. 21, 1971 Sun Electric Corporation Original application June 7, 1968, Ser. No. 735,309. Divided and this application Feb. 20, 1970, Ser. No. 13,040

2 l Appl. No. [22] Filed [45] Patented [73] Assignee [54] IMMEDIATELY RESPONSIVE FLUID FLOW OPERATED SWITCH WITH NORMALLY CLOSED SPRING CONTACT IN FLOW CHANNEL 3,134,875 5/1964 Forwald zoo/148R 1,009,338 11/1911 Perkins 200/819 2,826,754 3/1958 Carighan 200/81.9X 3,256,045 6/1966 Stelzer 200/81.9X FOREIGN PATENTS 1,108,593 4 1968 Gl'CfltBl'lifiln 200/83N 36,089 5/1926 Denmark ZOO/81.9 681,825 5/1930 France 200/819 1,149,434 5/1963 Germany ZOO/81.9

OTHER REFERENCES IBM Technical Disclosure; Pneumatic-to-Electric Transducer Plane; by H, Saghafi; Vol. 5, No. 11; April 1963 Primary Examiner-Robert K. Schaefer Assistant Examiner- Robert A. Vanderhye Altorney-Molinare, Allegretti, Newitt & Witcofi ABSTRACT: A fluid flow transducer for disposition in one or more fuel feedlines ofa fuel-injected engine for analyzing and timing the engine. The transducer includes a normally closed resilient movable contact in the transducer which is directly impinged by the flowing fuel to open an electrical circuit to generate signals which are indicative of the rotational speed of the engine and the frequency and time duration of fuel flow through each fuel line.

PATENTED UEEZI I9?! 3 wa /14W ATTORNEYS RELATED APPLICATIONS This application is a division of my copending US. application Ser. No. 735,309, filed June 7, 1968.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a fluid flow transducer and, more particularly, to a new and improved fluid flow transducer for measuring pulsating fuel flow characteristics in a fuel injector system for timing purposes or the like.

At this time no satisfactory electronic systems or methods have been devised to analyze and pinpoint fuel injector system malfunctions for fuel injected internal combustion engines, such as diesel engines, or to accurately time such engines particularly during high-speed operation. Such fuel systems, at present, are therefore difiicult to service and adjust and, at best, the prior methods and apparatus utilized for detecting malfunctions or for timing the engines have been crude and time consuming and do not produce accurate results. One such prior timing method and arrangement employs a sensing switch which is clamped around a flexible hose in the fuel line, the hose expanding and contracting in response to the fuel flow to operate the switch. Such indirect method and apparatus is, at best, only capable of coarse timing at low engine speeds and is ineffective at higher engine-operating speeds. lf poor timing and erratic injector nozzle operation at normal or high engine-operating speeds go undetected, poor engine performance results as well as increased fuel consumption and undesirable atmospheric pollution due to the resulting ineffcient combustion of the fuel.

When the apparatus of my invention is employed, the above-noted disadvantages are overcome. My transducer may be easily and rapidly installed in present fuel injector systems without extensive modification of the injector systems and is capable of use while the engine is operating at normal, as well as, high speeds. Where the transducer or trigger switch of my invention is incorporated in a plurality of fuel feedlines, the time duration of fuel flow through each injector nozzle can be rapidly determined and displayed electronically and a prompt comparison of the fuel flow through the nozzles and various other points in the system is rendered possible. Any malfunctions in the fuel system will be rapidly ascertained and pinpointed enabling rapid correction of the malfunctions. Moreover, a single transducer or trigger switch of my invention, may be used at either high or low 'engine speeds to trigger a timing device, a tachometer or other electronic device that would be used either as a part of engine-testing apparatus or the engine itself where it is desired to know the speed of the engine or where it is desired to time the engine. Finally, the transducer constructed in accordance with the principles of my invention is simple in construction and extremely reliable and accurate in operation and may be readily used by relatively unskilled technicians and personnel without a sacrifice of either accuracy or reliability.

In a principal aspect, the transducer of my invention is preferably positioned in fluid flow relationship in a flow system and includes a housing defining a flow passage therethrough. A first contact surface and a second movable contact surface are positioned in the flow passage and the movable contact surface is directly contacted by the flowing fluid and is moved thereby between first and second positions to open and close an electrical signal circuit.

These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING In the course of the description, reference will frequently be made to the attached drawings in which:

FIG. 1 is a schematic view of a fuel injector system incorporating an embodiment of the fluid flow analyzing apparatus of my invention;

FIG. 2 is an example of an oscilloscope presentation displaying the fuel flow characteristics of the system shown in FIG. 1;

H6. 3 is an enlarged exploded view of the preferred embodiment of a fluid flow transducer of the present invention; and

FIG. 4 is a cross-sectioned elevation view of the transducer in assembled form, taken along line 4-4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, a typical diesel fuel injection system is shown. A plurality of fuel injector nozzles l, 2, 3 and 4 are provided which are arranged in the like-numbered cylinders (not shown) of a diesel engine. A fuel line 10 feeds fuel oil from an appropriate fuel storage tank (not shown) to a suitable fuel filter arrangement 12. A fuel line 14 conducts the fuel from the filter arrangement 12 to an injector pump 16. The injector pump 16 pressurizes the fuel and passes the fuel selectively and in sequentially timed pulses to each of the fuel in jector nozzles 1, 2, 3 and 4 through nozzle feedlines l8, 19, 20 and 21, respectively. Frequently, the engine will become poorly timed or, due to wear and extended use, the injector nozzles l, 2, 3 and 4 or the injector pump 16 will malfunction and the quantity and time duration of fuel injected into the appropriate cylinders will become erratic and poor performance of the engine results.

In order to correct these problems, a fuel flow transducer or trigger switch 23 is located in fuel flow relationship in one or more of the nozzle feed lines l8, 19, 20 and 21. Referring particularly to FIGS. 3 and 4, the flow transducer 23 includes a pair of electrically conductive plates 25 and 26, each having a bored fuel flow passage 28 therethrough. Plate 25 carries an appropriate inlet connection 30 and plate 26 carries an outlet connection 32 in communication with their fuel flow passages 28. The inlet and outlet connections may be threaded to receive suitable coupling bushings for connection of each of the transducers 23 to its nozzle feedline. Sandwiched between the plates 25 and 26 are a pair of nonconductive gaskets 34 and 35 and located between the gaskets is a relatively thin conductive contact plate 36. The contact plate 36 includes a terminal tab 38 extending outwardly from its periphery. The gaskets 34 and 35 and the contact plate 36 are each provided with a centrally located aperture 40, 41 and 42, respectively, each of the apertures being positioned to align with each other and with the flow passages 28 of plates 25 and 26 when the transducer is assembled. The center aperture 42 of the contact plate 36 includes a resilient movable contact surface 44 extending toward the center of the aperture and formed integrally in one-piece construction with the contact plate 36. The movable contact surface 44 of such length that it extends across the flow passage 28 of plate 25 when the transducer is assembled. If the volume of flow is extremely high, a small hole may be provided in the contact surface 44 in alignment with flow passage 28 of plate 25 to relieve high back pressures. Each of the plates 25 and 26, gaskets 34 and 35, and contact plate 36 include a plurality of holes 46 about their circumference which are adapted to align with each other to receive bolts 48 having nuts 50 to hold the assembly together in close sandwiched relationship. The nuts 50 may be eliminated if desired by threading the bolts 48 directly into the holes 46 of plate 26. A suitable nonconductive sleeve 52 is journaled through the holes 46 to prevent conductive contact of the plates and the bolts 48. As shown in FIG. 4, one of the bolts 48 carries an electrical ground terminal 54 which is pressed between the head of the bolt 48 and the external face of plate 25 in electrical contacting relationship to the plate. It will be evident that other suitable methods of grounding plate 25 may be employed, if desired. The fuel flow passage 28 of plate 25 terminates in a slightly raised shoulder 56 which carries a stationary electrical contact surface 58 at its end. The shoulder extends into the aperture 40 of gasket 34 through substantially the thickness of that gasket, the contact surface 58 lying substantially in the plane of contact plate 36. An insulating ring 60 may be provided on the inner face of plate 26 to prevent contact of the resilient movable contact finger 44 with plate 26 and also to limit the travel of the contact finger when fuel is flowing through the fuel flow passages 28. An appropriate terminal connector 62 is provided on terminal 38 to facilitate the connection of the flow transducer in its electrical circuit as will be described in detail hereinafter.

One or more of the fuel flow transducers 23 are connected in circuit with an appropriate signal display device. For example as shown in FIG. 1, each of the flow transducers 23 is connected to an oscilloscope 63 of an engine performance analyzer. Although an oscilloscope is shown, it should be readily understood that any suitable display device may be utilized to display the signals produced by the transducers. One of the flow transducers 23 may also be connected to a suitable strobe timing light 64 or to a tachometer 65 where it is desired to sense the rotation of the engine. A single flow transducer thus may be utilized for timing the engine by selectively energizing the conventional strobe timing light 64 to illuminate appropriate timing marks on the fly wheel 66 of the engine. Moreover, a flow transducer 23 may be located in the inlet fuel line 14 of the injector pump 16 to indicate the condition of the injector pump. The electrical signals produced by the latter flow transducer may either be connected to a separate indicator 68 or may be connected in circuit with the oscilloscope 63 to provide for the display of information desired.

As a typical example, the signal display on the oscilloscope as generated by the flow transducers 23, is shown in FIG. 2. Each of the presentations 1, 3, 4 and 2 correspond to the firing order of each of the nozzles l, 2, 3 and 4. The width of each presentation is proportional to the time duration of fuel flow to each of the respective nozzles. It will be noted that the width of each of the presentations shown in FIG. 2 differ from each other, indicating a malfunction of the fuel injector system and a need for the adjustment of the system. Since each of the presentations corresponds with one of the fuel injector nozzles, a malfunction is rapidly pinpointed making possible rapid and effective correction of the malfunction.

When considering the above-detailed description of the preferred embodiment of my invention, its operation should be readily apparent. However, for the purpose of clarity, a detailed description of operation follows.

When the engine is running, fuel flows from the fuel storage tank (not shown), through fuel line 10, through the fuel filter arrangement 12 and through fuel line 14 to the fuel injector pump 16. The fuel injector pump 16, selectively and in sequentially timed pulses, pumps the fuel through nozzle feedlines 18, 19, and 21 to each of the fuel injector nozzles l, 2, 3 and 4, respectively. As the fuel passes through nozzle feedlines, the fuel enters the inlet connection 30 of plate 25 of each of the flow transducers 23, passing through the fuel flow passage 28 of plate 25, and moving the resilient movable contact surface 44 to the left, as viewed in FIG. 4, due to the force of the impinging fuel upon the contact surface. The fuel then continues through the fuel flow passage 28 in plate 26 and on to the fuel injector nozzle. Prior to the passage of fuel through the flow passage 28 of plate 25, the resilient movable contact surface 44 is undeformed and contacts the stationary contact surface 58 of plate 25. Electrical current flow is thereby established through the terminal connector 62, the terminal tab 38, the contact plate 36, the resilient movable contact surface 44, the stationary contact surface 58, the conductive plate 25 and to ground through the terminal 54 and a first signal is sent to the oscilloscope, timing light, etc. The timing light circuit may include an appropriate relay or the like for rendering its illumination properly responsive to the signal. When a pulse of fuel from the injector pump 16 is delivered to the nozzle feedline in which the transducer is located, the

flowing fuel enters the flow passage 28 of plate 25 and impinges upon the face of the resilient movable contact surface 44 deflecting the movable contact surface to the left, as viewed in FIG. 4, and out of electrical contact with the stationary contact surface 58. Thus, the electrical circuit is opened, and a second no-current-flow signal is transmitted to the oscilloscope, timing light, etc. Thus, the time duration of each pulse of fuel flow passing through each nozzle 1, 2, 3 and 4 is displayed upon the oscilloscope 63 and each of the time durations may be compared and readily adjusted, as necessary, to correct malfunctions. Also since the frequency of the fuel pulses is directly proportional to the rotating speed of the engine, each signal produced by transducer 23 in fuel line 18 may be utilized to operate the timing light 64 and/or tachometer 65. As mentioned previously a flow transducer 23 may also be installed in the inlet fuel line 14 to obtain information resulting from the pulsation of the fuel flow to the injector pump 16.

, The latter information may be displayed either on separate in dicator 68 or on the oscilloscope 63 to indicate the condition of the injector pump 16.

Although I have described the preferred embodiment of my invention primarily with reference to the fuel injector system of a four-cylinder diesel engine, it will be readily apparent that the principles of my invention may be employed to equal advantage in injector systems of other engines and engines using other fuels as well as numerous other fluid flow systems where it is desired to analyze the fluid flow characteristics of a pulsating fluid. It should also be understood that the embodiment of the invention which has been described is merely illustrative of an application of the principles of the invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.

I claim:

1. An immediate response high-pressure fluid flow transducer a housing comprising a first and second plate, each of said plates defining a fluid flow passage through said housing, and a third electrically conductive plate located between said first and second plates,

a first electrical tenninal connected to said housing and to a first contact surface within said housing, at least one of said first and second plates being electrically conductive and carrying said first contact surface and said first electrical terminal,

resilient urging means,

a second movable contact surface in said housing normally disposed in a first position by said resilient urging means and movable to a second position in response to the direct contact thereon of the flow of fluid through said fluid flow passage, the movement of said movable contact surface being immediately responsive to variations in said fluid flow,

a second electrical terminal connected to said second movable contact surface, said second movable contact surface and said second electrical terminal being carried on said third conductive plate,

said first and said second movable contact surfaces being positioned in said fluid flow passage and contacting each other to complete an electrical circuit between said terminals when said movable contact surface is disposed in one of said positions and opening said electrical circuit when said movable contact surface is disposed in the other of said positions.

2. The transducer of claim 1, wherein said second movable contact surface is resilient and extends into the flow of fluid in said fluid flow passage, said flow of fluid impinging upon said movable contact surface to move the surface to said second position.

3. An immediate response high-pressure fluid flow transducer comprising:

a housing defining a fluid flow passage therethrough,

a first electrical terminal connected to said housing and to a first contact surface within said housing,

resilient urging means,

a plate fixed in said housing, said plate having an aperture therein and a resilient portion of said plate extending into said aperture, said resilient portion forming a second movable contact surface, said second movable contact surface normally being disposed in a first position by said resilient urging means and movable to a second position in response to the direct contact thereon of the flow of fluid through said fluid flow passage, the movement of said movable contact surface being immediately responsive to variations in said fluid flow,

a second electrical terminal connected to said second movable contact surface,

said first and said second movable contact surfaces being positioned in said fluid flow passage and contacting each other to complete an electrical circuit between said terminals when said movable contact surface is disposed in one of said positions and opening said electrical circuit when said movable contact surface is disposed in the other of said positions.

4. The transducer of claim 3 wherein said electrical circuit is completed when said second movable contact surface is in said first position and said electrical circuit is opened when said second movable contact surface is in said second position.

5. The transducer of claim 3 wherein said first contact surface is stationary.

I I t l 

1. An immediate response high-pressure fluid flow transducer a housing comprising a first and second plate, each of said plates defining a fluid flow Passage through said housing, and a third electrically conductive plate located between said first and second plates, a first electrical terminal connected to said housing and to a first contact surface within said housing, at least one of said first and second plates being electrically conductive and carrying said first contact surface and said first electrical terminal, resilient urging means, a second movable contact surface in said housing normally disposed in a first position by said resilient urging means and movable to a second position in response to the direct contact thereon of the flow of fluid through said fluid flow passage, the movement of said movable contact surface being immediately responsive to variations in said fluid flow, a second electrical terminal connected to said second movable contact surface, said second movable contact surface and said second electrical terminal being carried on said third conductive plate, said first and said second movable contact surfaces being positioned in said fluid flow passage and contacting each other to complete an electrical circuit between said terminals when said movable contact surface is disposed in one of said positions and opening said electrical circuit when said movable contact surface is disposed in the other of said positions.
 2. The transducer of claim 1, wherein said second movable contact surface is resilient and extends into the flow of fluid in said fluid flow passage, said flow of fluid impinging upon said movable contact surface to move the surface to said second position.
 3. An immediate response high-pressure fluid flow transducer comprising: a housing defining a fluid flow passage therethrough, a first electrical terminal connected to said housing and to a first contact surface within said housing, resilient urging means, a plate fixed in said housing, said plate having an aperture therein and a resilient portion of said plate extending into said aperture, said resilient portion forming a second movable contact surface, said second movable contact surface normally being disposed in a first position by said resilient urging means and movable to a second position in response to the direct contact thereon of the flow of fluid through said fluid flow passage, the movement of said movable contact surface being immediately responsive to variations in said fluid flow, a second electrical terminal connected to said second movable contact surface, said first and said second movable contact surfaces being positioned in said fluid flow passage and contacting each other to complete an electrical circuit between said terminals when said movable contact surface is disposed in one of said positions and opening said electrical circuit when said movable contact surface is disposed in the other of said positions.
 4. The transducer of claim 3 wherein said electrical circuit is completed when said second movable contact surface is in said first position and said electrical circuit is opened when said second movable contact surface is in said second position.
 5. The transducer of claim 3 wherein said first contact surface is stationary. 